A volume fracturing method for horizontal shale gas wells at normal pressure

Abstract

The invention discloses a normal-pressure shale gas horizontal well volume fracturing method, which comprises the following steps that: compressibility evaluation; crack parameter optimization; perforation parameter optimization; crack communication optimization; fracturing construction parameter optimization; propping agent parameter optimization; and after-pressure flowback parameter optimization. By use of the method, the development technical level and the economic benefit of a shale gas reservoir can be improved.

Description

technical field [0001] The invention belongs to the technical field of oil and gas field exploration and development, and in particular relates to a method for volume fracturing of a normal-pressure shale gas horizontal well. Background technique [0002] At present, domestic shale gas fracturing has made a breakthrough in the Longmaxi high-pressure strata of the lower Silurian in the marine facies, such as Sinopec in the Jiaoshiba area of ​​Fuling, Chongqing and the Changning-Weiyuan area of ​​PetroChina, especially the Jiaoshiba shale The gas field has been truly commercially developed. [0003] However, in the normal pressure formations of marine Longmaxi, such as Chongqing Pengshui area, Dingshan area and many other normal pressure formations outside the Sichuan Basin, although the engineering technology has been successful, the gas production is low and the economic benefits are low. Get a commercial breakthrough. However, these atmospheric shale gas reserves are huge...

AI Technical Summary

Problems solved by technology

[0006] 2) In order to increase the thoroughness of the reconstruction, more fluid volume and proppant dosage are one-sidedly pursued during single-stage fracturing, resulting in too long flowback cycle of fracturing fluid after fracturing, resulting in a certain liquid lock effect, which is extremely unfavorable to gas production after fracturing ;

As a result of the above-mentioned fracture characteristics, the fracturing fluid flowback rate after fracturing remains high (about 50% in Pengshui, but only 1-3% in Jiaoshiba), and the initial production after fracturing is difficult to break through 3×104m3 / d. The output is generally lower than 1.5×104m3 / d, which is difficult to achieve the effect of economic development;

[0008] 4) The mechanism of fracturing fluid flowback after normal pressure shale gas pressure is unclear. Therefore, the timing of fracturing fluid flowback and the optimization of flowback system are lack of pertinence

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